The future of the North's power-sharing Executive came under renewed scrutiny today after Sinn Fein tabled an urgent Assembly question about the Robinson controversy.
Deputy First Minister Martin McGuinness has the power to walk away from his partnership with the DUP if Peter Robinson is toppled.
Republicans are keen to see progress on devolving policing and justice powers from London to Belfast as their price for remaining in government.
Mr McGuinness has sought answers on whether Assembly rules were breached after Mr Robinson failed to report his wife Iris to the parliamentary authorities for obtaining loans for her toyboy lover.
Sinn Fein president Gerry Adams said: "The failure of the DUP to fulfil its political commitments and work the political institutions, as it agreed, on the basis of partnership and equality, has led to a considerable lack of public confidence in the political institutions."
Sinn Fein wants policing and justice powers devolved as soon as possible. The DUP is under pressure from unionist hardliner Jim Allister, who opposes Sinn Fein in government, and wants to wait until finances and community confidence are in place.
If Mr Robinson falls, the post of First Minister and Deputy First Minister, held by Mr McGuinness, would have to be filled. Sinn Fein could delay nominating unless the DUP agreed to a timescale for the devolution of policing and justice. If this was not resolved within seven days it would fall.